JPH06322178A - Salt-resistant absorbent composition - Google Patents

Abstract

PURPOSE:To provide the subject composition composed of a water absorb resin and a specified surfactant, excellent in water absorption from a saline solution or an aqueous solution of a polyvalent ion, capable of ready production and applicable to wide industrial use. CONSTITUTION:The objective composition is composed of (A) 100 pts.wt. water absorb resin (preferably a carboxyl group-containing starch-acrylonitrile copolymer, etc.) and (B) 1 to 300 pts.wt., preferably 5 to 150 pts.wt. alkanolamide group-containing nonionic surfactant (preferably lauric acid diethanolamide or coconut oil fatty acid diethanolamide). This composition is produced recommendably by blending the component (A) with the component (B) or by adding the component (B) during the process for production of the component (A). In addition, the shape of the component (A) is preferably a powder having a particle size distribution that particles of >=90wt.% are 0.1 to 0.9mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a salt-resistant absorbent composition having excellent absorption performance for aqueous salt solutions.

[0002]

2. Description of the Related Art Heretofore, a hydrophilic cross-linked polymer called a water-absorbent resin has been known as a granular water-absorbing agent having an absorbing ability for an aqueous liquid. Examples of these water absorbent resins include starch-acrylic acid salt copolymers, crosslinked polyacrylic acid salts, crosslinked copolymers of acrylic acid and its salts with other monomers, and isobutylene-maleic anhydride copolymers. Various resins such as cross-linked polymers, polyvinyl alcohol- (meth) acrylic acid copolymer, modified cellulose derivatives, modified polyethylene oxide, modified polyvinyl alcohol are known, and are mainly used for sanitary materials such as disposable diapers and sanitary products. Came.

However, the conventional water-absorbent resin has a high water-absorbing ability with respect to water, but its absorbing ability is significantly lowered in the presence of an electrolyte such as an inorganic salt. Proposals have been made to improve these. For example, a method of heating and insolubilizing a polysaccharide containing uronic acid or a salt thereof as a structural unit by crosslinking by heating (JP-A-56-5137), graft-polymerizing a water-soluble monomer and a crosslinking agent onto the polysaccharide. , If necessary, further heat treatment (Japanese Patent Publication No. 3-68889)
JP-A-56-5138), a method of mixing an ion sealing agent with a water-absorbent resin (JP-A-56-89838), and the like. However, in any case, since the improvement is not sufficient, the fact is that it has not been put to practical use.

[0004]

In view of the above problems, the inventors of the present invention have earnestly studied a salt-resistant absorbent composition having excellent absorption performance for an aqueous salt solution, and as a result, arrived at the present invention.

That is, the present invention comprises a water absorbent resin (A),
A nonionic surfactant having an alkanolamide group (B), and (B) with respect to 100 parts by weight of (A).
Is 1 to 300 parts by weight.

In the present invention, the water-absorbent resin (A) is usually a hydrophilic cross-linking material having an absorption capacity of about 100 to 1000 times its own weight with respect to water and about 20 to 60 times with respect to physiological saline. Polymer, with carboxylic acid (salt) as its structural unit
The group [refers to a carboxylic acid and / or a carboxylic acid group.
The same description is used below. ], At least one of a sulfonic acid (salt) group, a phosphoric acid (salt) group, a tertiary amino group, a quaternary ammonium group, a hydroxyl group, a polyoxyethylene group, and the like.
The type and manufacturing method of the resin are not particularly limited as long as it is a water-absorbent resin having one hydrophilic group. Examples of this water absorbent resin include starch-acrylic acid (salt) copolymers described in JP-B-53-46199 and JP-B-53-46200, JP-B-54-30710, JP-A-56- Crosslinked or self-crosslinked polyacrylic acid salt by the reverse phase suspension polymerization method described in 26909 publication, crosslinked polyacrylic acid (salt) obtained by aqueous solution polymerization described in JP-A-55-133413, etc., JPA
52-14689, Saponified copolymer of vinyl ester and unsaturated carboxylic acid or its derivative described in JP-A-52-27455, JP-A-58-2312, JP-A-61-36309 Sulfonic acid (salt) group-containing water-absorbent resin, isobutylene-maleic anhydride copolymer crosslinked product, starch-acrylonitrile copolymer hydrolyzate, crosslinked carboxymethyl derivative, crosslinked polyethylene oxide derivative, etc.
Examples thereof include crosslinked polyvinyl alcohol derivatives and polyacrylamide partially hydrolyzed products. Preferably, starch-acrylic acid (salt) having a carboxylic acid (salt) group,
Cross-linked polyacrylic acid (salt), saponified copolymer of vinyl ester and unsaturated carboxylic acid or its derivative, isobutylene-maleic anhydride copolymer cross-linked product, starch-
It is a hydrolyzate of an acrylonitrile copolymer, a crosslinked carboxymethyl derivative, or a partial hydrolyzate of polyacrylamide. Further, a water absorbent resin obtained by further surface-crosslinking the above water absorbent resin can also be suitably used. You may use together 2 or more types of said water absorbent resin.

The shape of the water-absorbent resin is not particularly limited as long as it is powdery, and it is granular, granular, granulated, flake shaped,
It may be in any shape such as a lump, pearl or fine powder. 90% by weight or more is a powdery granule having a particle size distribution of 1 mm or less, and particularly preferably 90% by weight or more.
It is a water-absorbent resin having a particle size distribution of 0.1 to 0.9 mm.

In the present invention, the surfactant (B) is a nonionic surfactant having an alkanolamide acid group. Preferred is a nonionic surfactant having an alkanolamic acid group consisting of a C _{10 to} C ₂₄ fatty acid. If the carbon number is less than 10 or more than 24, the effect is small. Examples of (B) include lauric acid diethanolamide, lauric acid monoisopropanolamide,
Palm oil fatty acid diethanolamide Palm oil fatty acid monoethanolamide, stearic acid monoethanolamide and the like, preferably lauric acid diethanolamide and palm oil fatty acid diethanolamide. In addition, these activators may contain a small amount of diethanolamine.
Further, two or more kinds of the above surfactants may be used in combination.

The ratio of (A) to (B) is such that the amount of (B) is usually 1 to 300 parts by weight, preferably 5 to 150 parts by weight, relative to 100 parts by weight of (A). Even if the amount of (B) exceeds 300 parts by weight, the effect corresponding to the added amount cannot be obtained, which is uneconomical. On the other hand, if it is less than 1 part by weight, the effect of improving salt resistance cannot be obtained.

Conventionally, as a combination of a water-absorbent resin and a surfactant, for example, the water-absorbent resin is treated with a cationic surfactant having one or more C _{12 to} C ₂₄ alkyl groups to improve Mamako and powder. There are proposals such as those with improved fluidity (Japanese Patent Laid-Open No. 61-69854), but since the salt water absorption resistance is not mentioned, the salt resistance of the absorbent (improvement of salt solution absorption is improved. ) Is essentially different from the present invention in which Further, the surfactant that can be preferably used also differs.

As the method for producing the absorbent composition of the present invention, the method of mixing (A) with (B), the method of absorbing (A) the aqueous solution of (B), and the step of producing (A) Method of adding (B) [eg (B) during polymerization of (A)
Or (B) is added to the polymer gel of (A)]. The preferred method is or.

As in the present invention, the reason why the water-absorbent resin and the nonionic surfactant having an alkanolamide group show a high absorption performance for the salt solution are not clear, but the network polymer chain of the water-absorbent resin is not clear. , In particular, a polymer chain having a carboxylic acid group and a surfactant having an alkanolamide group interact with each other, and the surfactant has a function of preventing salts from entering the network polymer of the water absorbent resin. However, as a result, it is considered that the salt solution exhibits high absorption performance similar to that of water.

In the absorbent composition of the present invention, a filler, water as an additive, organic powder (eg pulp powder, cellulose derivative, natural polysaccharides, etc.), inorganic powder (eg zeolite, ultrafine silica, alumina) , Bentonite, activated carbon, etc.), antioxidants, preservatives, bactericides, colorants, fragrances, other surfactants, etc. can be added as necessary, and these amounts are usually relative to the weight of the composition. It is 10% by weight or less.

[0014]

The present invention will be further described below with reference to Examples and Comparative Examples, but the present invention is not limited to these. The swollen gel volume ratio and the absorption amount of the absorbent composition were measured by the following methods. The amount added below is the amount added of the active ingredient.

Swelling gel volume ratio: test tube (φ = 14 mm; height 1
(6.5 cm), water-absorbent composition 0.1 g, deionized water 15 g
After swelling, a predetermined amount of salt (0.135 g of sodium chloride in the case of physiological saline) is added thereto and the swelling gel height (a) after standing for 1 hour is measured. On the other hand, 0.1 g of a water-absorbent resin to which no surfactant has been added is swollen with 15 g of deionized water, to which the same kind and the same amount of salt are added, and 1
The swollen gel height after standing for a period of time (b) is measured, and the swollen gel volume ratio is determined by the following formula. Swelling volume ratio (%) = (a / b) × 100 Absorption amount: The entire amount of the gel whose swollen gel volume ratio was measured is transferred to a 250 mesh nylon net tea bag and drained for 15 minutes to increase the weight (c). Is measured and the water absorption is calculated by the following formula. Absorption amount (g / g) = c × 10

Example 1 0.1 g of cross-linked sodium acrylate-based water-absorbent resin ("Sunwet IM-5000D" manufactured by Sanyo Kasei Co., Ltd.)
And coconut oil fatty acid diethanolamide (“Profan 2012E” manufactured by Sanyo Kasei Co., Ltd .; active ingredient 98%)
The absorbent composition (a) of the present invention was obtained by adding and mixing 0.2 g. Table 1 shows the results of measuring the swollen gel volume ratio and the amount of absorption of this absorbent composition in physiological saline. The absorbed amount of Sunwet IM-5000D with respect to physiological saline was 48 g / g.

Examples 2 and 3 In Example 1, the surfactant "Prophane 2012" was used.
Absorbent compositions (b) and (c) were obtained in the same manner as in Example 1 except that the addition amount of "E" was changed as follows. The results of measuring the swollen gel volume ratio and the absorption amount are shown in Table 1. Absorbent composition (b): amount of Prophan 2012E added 0.1 g Absorbent composition (c): amount of Prophan 2012E added 0.01 g

Example 4 In Example 1, the surfactant "Prophane 2012" was used.
An absorbent composition (d) was obtained in the same manner as in Example 1 except that "E" was replaced with lauric acid diethanolamide ("Profan AA-62EX" manufactured by Sanyo Chemical Industry Co., Ltd.). Table 1 shows the results of measuring the absorption amount.

Example 5 In the same manner as in Example 1 except that the amount of sodium chloride in measuring the swollen gel volume ratio in Example 1 was changed to 0.3 g, the swollen gel volume ratio and absorption amount in 2% saline were measured. The measured results are shown in Table 1. In addition, Sunwet IM-500
The amount absorbed by 0D of 2% saline was 39 g / g.

Example 6 The swollen gel volume ratio to 1% magnesium sulfate was the same as in Example 1 except that 0.15 g of magnesium sulfate was used instead of the seed and amount of the salt in measuring the swollen gel volume ratio. Table 1 shows the results of measuring the absorption amount. The absorption amount of Sunwet IM-5000D with respect to 1% magnesium sulfate was 5 g / g.

Example 7 The same amount of "Prophane 2012E" was used with respect to the solid content of the polymer gel in the production of the crosslinked sodium acrylate-based water absorbent resin.
Was added and dried to obtain an absorbent composition (e). Table 1 shows the results of measuring the swollen gel volume ratio and the absorption amount of this product in physiological saline.

Example 8 The cross-linked sodium acrylate-based water-absorbent resin in Example 1 was added to "Sunwet IM-300" (manufactured by Sanyo Kasei Co., Ltd.), which is a cross-linked starch-acrylate graft copolymer. An absorbent composition (he) was obtained in the same manner as in Example 1 except that it was replaced. Table 1 shows the results of measuring the swollen gel volume ratio and the absorption amount of this product in physiological saline.
The absorption amount of Sunwet IM-300 with respect to physiological saline was 53 g / g.

Comparative Example 1 In Example 1, the surfactant "Prophane 2012" was used.
Example 1 except that the amount of "E" added was changed to 0.0005 g.
A comparative composition (g) was obtained in the same manner as described above. Table 1 shows the results of measuring the swollen gel volume ratio and the amount of absorption in these physiological saline solutions.

Comparative Example 2 In Example 1, the surfactant "Prophane 2012" was used.
A comparative composition (H) was obtained in the same manner as in Example 1 except that "E" was replaced with capryl diethanolamide. Table 1 shows the results of measuring the swollen gel volume ratio and the amount of absorption in these physiological saline solutions.

[0025]

[Table 1]

[0026]

The salt-resistant water-absorbent resin of the present invention has the following features and effects. Excellent absorption performance for salt water. It exhibits excellent absorption performance for aqueous solutions of polyvalent ions. It can be manufactured by a simple operation.

Because of the above effects, the absorbent composition having excellent salt resistance of the present invention absorbs electrolyte-rich urine, blood, etc., such as disposable diapers, sanitary products, puerperium mats and medical underpads.・ Various sanitary materials used for gelation; Coagulants for water-containing substances that contain high concentrations of electrolytes such as industrial wastewater and seabed sludge; Sealing materials for civil engineering and shields that require high swelling power against seawater and hard water Applications such as mud-prevention agents for construction methods and waterproofing agents for submarine cables; applications such as curing materials after concrete placement and concrete admixtures;
It can be used for a wide range of industrial applications such as disposable body warmers and absorbents for high-concentration salt solutions such as desiccants containing calcium chloride as the main ingredient.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Tanaka 1-11, Hitotsubashi Honmachi, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd.

Claims (6)

[Claims] 1. A water-absorbent resin (A) and a nonionic surfactant (B) having an alkanolamide group,
An absorbent composition in which (B) is 1 to 300 parts by weight with respect to 100 parts by weight of (A). 2. (B) is a C ₁₀ -C ₂₄ fatty acid and C ₂ -C ₅
The absorbent composition according to claim 1, which is an amide compound with the alkanol of. 3. The absorbent composition according to claim 1, which is (B) lauric dialkanolamide or coconut oil fatty acid alkanolamide. 4. (B) is 5 per 5 parts by weight of (A).
To 150 parts by weight, The absorbent composition according to any one of claims 1 to 3. 5. (A) is a starch-acrylic acid (salt) copolymer, a crosslinked polyacrylic acid (salt), a saponified product of a vinyl ester and an unsaturated carboxylic acid or a derivative thereof, isobutylene-maleic anhydride. At least one selected from the group consisting of a copolymer crosslinked product, a starch-acrylonitrile copolymer hydrolyzate, a crosslinked carboxymethylcellulose derivative, and a polyacrylamide partial hydrolyzate.
2. A water-absorbent resin containing different carboxylic acid groups.
The absorbent composition according to any one of 4 to 4. 6. The absorbent composition according to any one of claims 1 to 5, wherein the absorption capacity for physiological saline is 50 to 150 times its own weight.